DIY Home Improvement Forum banner

Making Furnace Quieter

2022 Views 8 Replies 8 Participants Last post by  gregzoll
My forced hot air furnace is directly next to my home theater room and it is behind louvered doors (for airflow), so it can get pretty loud when it turns on it. I’m looking for some fairly cheap/easy ideas to minimize noise.

I’m not an HVAC expert, so I don’t want to take anything apart.

My blower fan is currently set to the Medium-High setting on scale that goes High, Medium-High, Medium, Low. I was thinking about lowering the fan to Medium to reduce the air velocity, which I assume would reduce noise.

Also, the main duct work coming off of the furnace is just sheet metal with zero insulation on it. I don’t want to do anything like opening it up or changing it, but I was thinking about buying something like Roxul Enerwrap (®+80) to wrap around the main ducts. Would that be a good idea?
1 - 9 of 9 Posts
How hot is the air coming out of the supply registers.
How hot is the air coming out of the supply registers.
Not that hot I guess.
He was looking for a temperature. You may be able to turn your fan speed down depending on the temp. Get several locations if possible
Use a thermometer to measure the air in the hot air plenum. Choose a location that is close to the furnace but around a corner in the plenum sheet metal so that its not in sight of the heat exchanger. ( not picking up radient heat from the exchanger). Run the furnace for 10 minutes and measure the temp.
There should probably already be a hole in the ducting (now taped over) that the installers used to do this same test.
Take that temp reading and subtract the room temp shown on the thermostat from it. Compare that temp number with the temp rise listed on the furnace identity plate.
That will tell you if you should lower the fan speed which will cause the furnace to run hotter than before.
Let us know what the figures are.
When you say airflow do you mean that the furnace return is on the furnace and it draws through the louvered doors? If so, is there anyway to connect to the return and relocate it farther from the furnace? Return vents right on the furnace are usually noisy.
Is the noise an air movement noise or a mechanical noise from the furnace itself? It's kind of hard to determine exactly what you are objecting to by the information provided

Is there a wall or walls and/or doors (other than the louvered doors) between the theater and the furnace?

If the noise is mostly coming through the louvered door you can put a sound trap in front of the door. It's basically and L shaped wall with sound absorbing material on the inside of it towards the furnace.
  • Like
Reactions: 1
becareful lowering the air speed going acrossed heat exchanger it may have been set for proper tempeture rise....lowering it could cause premature heat exchanger failure resulting in high levels of carbon monoxide going into house so as was mentioned check air tempeture...ben sr....thanks how just now read your post....
Sounds like a poor design, whoever designed the home theater for no separation from the hvac equipment. Only best thing you could do, would be to update the equipment with a Variable Speed multi-stage unit, or relocate the hvac equipment into a different area farther from your home theater.

My home theater is my living room, and personally when the furnace kicks on, it does not even bother me. Even when in the Summer months, when it kicks into high speed for cooling. There really are other things to worry about, than the sound of airflow from the hvac system.
  • Like
Reactions: 1
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.